Rhodotorula portillonensis sp. nov., a basidiomycetous yeast isolated from Antarctic shallow-water marine sediment Federico Laich, 1 Inmaculada Vaca 2 and Renato Cha ´ vez 3 Correspondence Renato Cha ´ vez renato.chavez@usach.cl 1 Instituto Canario de Investigaciones Agrarias, Ctra. Boquero ´ n s/n, Valle de Guerra, Santa Cruz de Tenerife, Spain 2 Departamento de Quı ´mica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, N ˜ un ˜ oa, Santiago, Chile 3 Departamento de Biologı ´a, Facultad de Quı ´mica y Biologı ´a, Universidad de Santiago de Chile (USACH), Alameda 3363, Estacio ´ n Central, 9170022, Santiago, Chile During the characterization of the mycobiota associated with shallow-water marine environments from Antarctic sea, a novel pink yeast species was isolated. Sequence analysis of the D1/D2 domain of the LSU rDNA gene and 5.8S-ITS regions revealed that the isolated yeast was closely related to Rhodotorula pallida CBS 320 T and Rhodotorula benthica CBS 9124 T . On the basis of morphological, biochemical and physiological characterization and phylogenetic analyses, a novel basidiomycetous yeast species, Rhodotorula portillonensis sp. nov., is proposed. The type strain is Pi2 T (5CBS 12733 T 5CECT 13081 T ) which was isolated from shallow-water marine sediment in Fildes Bay, King George Island, Antarctica. Introduction It has been largely shown that yeasts inhabit several marine environments, such as coastal, estuarial, offshore and deep-sea habitats, among others (Gadanho et al., 2003; Nagahama, 2006; Fell, 2012; Nagano & Nagahama, 2012). However, the Antarctic marine ecosystem remains largely unexplored and few studies have investigated the yeasts that inhabit the Antarctic seas. To date, yeasts from the genera Candida, Cryptococcus, Cystofilobasidium, Gueho- myces, Leucosporidium, Metschnikowia, Mrakia, Rhodospo- ridium, Rhodotorula, Sympodiomyces, Sakaguchia and Sporopachydermia have been isolated from seawater, marine sediments, invertebrate organisms and algae, among other Antarctic marine environments (Nagahama, 2006; Kutty & Philip, 2008; Shivaji & Prasad, 2009; Loque et al., 2010; Hua et al., 2010; Song et al., 2010; Buzzini et al., 2012; Vaca et al., 2013). The importance of the study of Antarctic marine yeasts has been pointed by genus-wise distribution studies, which showed that marine yeasts from Antarctic oceans have the least similarity compared with the yeast biodiversity from the other oceans (Kutty & Philip, 2008). Hence, Antarctic oceans are interesting environments for the search of new yeasts. The archipelago of the South Shetland Islands lies near the northern tip of the Antarctic Peninsula. This archipelago is separated from the peninsula by the Bransfield Strait. King George Island is the largest island among South Shetland Islands. The north side of the King George Island limits with the stormy Drake Passage, but at the south side, in front of the Bransfield Strait, there are three protected bays, one of them is Fildes Bay. Differing from other Antarctic regions, which are mostly cold deserts, with dry continental air, strong winds, and a sparse flora and fauna, the Fildes Bay area represents an example of a periglacial landscape, characterized by a cool, moist climate and a well-developed plant and animal life (Simonov, 1977). In summer, the average temperature usually does not exceed 0 u C, while in winter season average temperature is around 212 u C, and although snow falls throughout the year, it also can rain during the summer (annual rainfall is around 1250 mm). In Fildes Bay, the surface water temperature varies between 0.5 and 2 u C during the summer, and the water does not freeze even in winter in some years (Sakurai et al., 1996). Several studies on yeast diversity of King George Island have been performed, but most of them have been mainly focused on the diversity present in soil samples (see Abbreviations: ITS, internal transcribed spacer; LSU, large subunit. The GenBank/EMBL/DDBJ accession number for the D1/D2 domain of the large subunit (LSU) and the 5.8-ITS rDNA sequences of Rhodotorula portillonensis sp. nov. Pi2 T are JQ769312 and JQ769323, respectively. The MycoBank accession number for Rhodotorula portillonensis sp. nov. is MB 804507. A supplementary table and a supplementary figure are available with the online version of this paper. International Journal of Systematic and Evolutionary Microbiology (2013), 63, 3884–3891 DOI 10.1099/ijs.0.052753-0 3884 052753 G 2013 IUMS Printed in Great Britain